Try this site for medical English:

http://www.englishmed.com/

There are four catagories : doctors, nurses, pharmacists and general medical staff.

I used it for some time with doctors, they use real English speakers for the dialogues and they are done in cartoon form. Real good - there is also a resource centre for each dialogue with various exercises: matching, collocations, gap filling, document gap filling, word order and hangman.

Hope you like it as much as I do.

Regards,
Janet